A heart attack [or Myocardial Infarction (MI)] occurs when the supply of blood and oxygen to an area of heart muscle is blocked, usually by a clot in a coronary artery. Often, this blockage leads to arrhythmias (irregular heartbeat or rhythm) that cause a sever decrease in the pumping function of the heart and may bring about sudden death. If the blockage is not covered within a few hours, the affected heart muscle will die and be replaced by scar tissue.
A heart attack is a life-threatening event. Everyone should know the warning signs of a heart attack and how to get emergency help. Many people suffer permanent damage to their hearts or die because they do not get help immediately.
If care is thought soon enough, blood flow in the blocked artery can be restored in time to prevent permanent damage to the heart. Yet, most people do not seek medical care for 2 hours or more after symptoms begin. Many people wait 12 hours or longer.
Heart Attack Warning Signs
Cardiac arrest strikes immediately and without warning. Some heart attacks are sudden and intense – but most heart attacks start slowly, with mild pain or discomfort.
Often people affected are not sure what's wrong and wait too long before getting help.
The following signs should not be ignored – they can mean a heart attack is happening:
oChest discomfort. Most heart attacks involve discomfort in the center of the chest that lasts more than a few minutes, or that goes away and comes back. It can feel like uncomfortable pressure, squeezing, fullness or pain.
oDiscomfort in other areas of the upper body. Symptoms can include pain or discomfort in one or both arms, the back, neck, jaw or stomach.
oShortness of breath. May occur with or without chest discomfort.
oOther signs: These may include breaking out in a cold sweat, nausea or lightheadedness.
As with men, women's most common heart attack symptom is chest pain or discomfort. But women are somewhat more likely than men to experience some of the other common symptoms, particularly shortness of breath, nausea / vomiting, and back or jaw pain.
Even though the symptoms of a heart attack at times can be vague and mild, it is important to remember that heart attacks producing no symptoms or only mild symptoms can be just as serious and life-threatening as heart attacks that cause severe chest pain.
Too often patients disease heart attack symptoms to "indigestion," "fatigue," or "stress," and consequentially delay seeking medical medical attention. One can not overemphasize the importance of seeking prompt medical attention in the presence of symptoms that suggest a heart attack. Early diagnosis and treatment saves lives, and delays in reaching medical assistance can be fatal. A delay in treatment can lead to permanently reduced function of the heart due to more intensive damage to the heart muscle. Death also may occur as a result of the sudden sunset of arrhythmias.
What causes a heart attack?
Atherosclerosis is a gradual process in which plaques (collections) of cholesterol are deposited in the walls of arteries. Cholesterol plaques cause hardening of the arterial walls and narrowing of the inner channel (lumen) of the artery. Arteries that are narrowed by atherosclerosis can not deliver enough blood to maintain normal function of the parts of the body they supply. For example, atherosclerosis of the arteries in the legs causes reduced blood flow to the legs. Reduced blood flow to the legs can lead to pain in the legs while walking or exercising, leg ulcers, or a delay in the healing of wounds to the legs.
In many people, atherosclerosis can remain silent (causing no symptoms or health problems) for years or decades. Atherosclerosis can begin as early as the teenage years, but symptoms or health problems usually do not arise until later in adulthood when the arterial narrowing becomes severe. Coronary artery disease refers to the atherosclerosis that causes hardening and narrowing of the coronary arteries. Diseases caused by the reduced blood supply to the heart muscle from coronary atherosclerosis are called coronary heart diseases (CHD). Coronary heart diseases include heart attacks, sudden unexpected death, chest pain, abnormal heart rhythms, and heart failure due to weakening of the heart muscle.
Atherosclerosis and angina pectoris
Angina pectoris (also referred to as angina) is chest pain or pressure that occurs when the blood and oxygen supply to the heart muscle can not keep up with the needs of the muscle. When coronary arteries are narrowed by more than 50 to 70 percent, the arteries can not increase the supply of blood to the heart muscle during exercise or other periods of high demand for oxygen. An insufficient supply of oxygen to the heart muscle causes angina.
Angina that occurs with exercise or exertion is called exertional angina.
Exertional angina usually feels like pressure, heaviness, squeezing, or aching across the chest. This pain may travel to the neck, jaw, arms, back, or even the teeth, and may be accompanied by shortness of breath, nausea, or a cold sweat. Exertional angina typically lasts from 1 to 15 minutes and is relieved by rest or placing a nitroglycerin tablet under the tongue. Both resting and nitroglycerin decrease the heart muscle's demand for oxygen, thus relieving angina. Exertional angina may be the first warning sign of advanced coronary artery disease.
Chest pains that just last a few seconds rarely are due to coronary artery disease.
Angina also can occur at rest. Angina at rest more commonly indicates that a coronary artery has narrowed to such a critical degree that the heart is not receiving enough oxygen even at rest.
While heart attacks can occur at any time, most heart attacks occur between 4:00 AM and 10:00 AM because of the higher blood levels of adrenaline released from the adrenal glands during the morning hours. Increased adrenaline, as previously discussed, may contribute to rupture of cholesterol plaques.
Approximately 50% of patients who develop heart attacks have warning symptoms such as exertional angina or rest angina prior to their heart attacks.
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